This invention relates to hot melt inks.
Hot melt inks are solid at room temperature and liquid at temperatures above room temperature. Hot melt inks can be used, for example, in digital to print methods. During printing, the ink is heated until it becomes liquid, and is then ejected through a printhead onto a substrate. The ink then solidifies on the substrate.
Hot melt inks have been be used, for example, on food packaging. However, it is sometimes desirable to mark directly onto various food products, such as eggs and cheese. Marking directly onto foods allows for additional product identification, as well as the only available identification in cases where the product is sold with little to no packaging, or in cases where the product is not packaged until the point of sale.
The conventional methods for printing directly onto food products include applying liquid inks through stamping, flexography, gravure printing, or continuous ink jet printing technologies. Stamping, flexography, and gravure printing are not digital to print, and can sometimes result in poor print quality. Continuous ink jet printing can result in a mark with low resolution.